Hydraulic rams



May 9, 1961 H. NORTON ET AL 2,983,552

HYDRAULIC RAMS Filed Dec. 7, 1959 2 SheetsSheet 1 NTORS HE k'roN Huszm' LESLIE B- NORTON DouGLAS E NQR O ATTORNEYS May 9, 1961 H. NORTON ET AL 2,983,552

HYDRAULIC RAMS Filed Dec. 7, 1959 2 Sheets-Sheet 2 /o' @r I 27 INVENTORS HENRY Noa'ram Hussm' V. Nana-MN Lasuz E- N R Dozaeuas ENoRW 2,983,552 Patented May 9, 1961 filice HYDRAULIC RAMS Henry Norton, Hubert Veare Norton, Leslie Buckingham Norton, and Douglas Edwin Norton, all of Horley, England, assignors to Norton Tool Company Limited, Horley, England, a company of Great Britain Filed Dec. 7, 1959, Ser. No. 857,794

Claims priority, application Great Britain Dec. 9, 1958 3 Claims. (Cl. 308-3) This invention relates to hydraulic rams of the kind in which a movable member of the ram is guided longitudinally by a fixed guide sleeve which surrounds the movable member. Rams of this kind are used, for instance, in hydraulic presses and other machine tools. In course of time the movable member or the guide sleeve or both may wear, resulting in inaccurate guiding. It is an object of the invention to provide a simple way of compensating for such wear.

According to the present invention, in a hydraulic ram of the kind specified the guide sleeve is slit longitudinally and has two cheeks with flat facing surfaces bounding the slit, a fiat-sided spacer is inserted between these checks, and clamping means are provided for clamping the checks of the guide sleeve firmly against the sides of the spacer.

When the wear of the guide sleeve and/ or the movable member is such that adjustment is required, the clamping means are released, the spacer is removed and is thinned down by an appropriate amount as by grinding or by removal of a shim, and is reinserted, or a slightly thinner spacer is inserted, and the clamping means are retightened. This draws the cheeks of the guide sleeve slightly closer together which has the effect of slightly reducing the cross-section of the guide way. Although the cross-sectional shape of the guide way may also be distorted slightly, the extent of the adjustment in relation to the size of the guide way is so small that this distortion is insignificant.

Where the guide way in the guide sleeve is of circular cross section and it is necessary to prevent rotation of the movable member, the inner end of the spacer may project inwardly into a longitudinal groove in the movable member so that it also acts as a key or gib.

In one such form of the invention the inner end of the spacer has bevelled longitudinal edges, the groove in the movable member has correspondingly sloping side walls, and provision is made for adjusting the spacer in the radial direction whereby wear in the groove or at the inner end of the spacer can be taken up. This can be achieved, for instance, by making the spacer in two parts, namely an inner part and an outer part, the position of the outer part being fixed, for instance by the said clamping means, and the position of the inner part in relation to the outer part being adjustable, for instance by adjusting screws passing through the outer part.

The invention is applicable either to rams in which the movable member is constituted by the ram piston, or to inverted rams in which the movable member is constituted by the ram cylinder, the ram piston being fixed.

In one form of the invention the movable member is provided with an adjustable stop collar, and the adjacent end'of the guide sleeve is provided with a flat surface which constitutes a fixed stop for engagement with the stop collar to define one end of the stroke of the ram. Similar stops may be provided at the opposite end of the guide sleeve to define the other end of the stroke.

The guide sleeve may be provided with additional longitudinal bores if desired, to guide additional longitudinally movable members or to receive fixed guide rods for a movable platen or the like.

The invention may be performed in various ways, and a specific embodiment with some modifications will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a vertical plan view of one form of guide sleeve embodying the invention;

Figure 2 is a front elevation of the guide sleeve shown in Figure 1;

Figure 3 shows a modified form of guide sleeve for a ram having also an adjustable lower stop collar; and

Figure 4 is a top plan view of a guide sleeve for a ram provided with lateral guide rods.

The guide sleeve shown in Figures 1 and 2 comprises a body 10 provided with a flat back surface 11 adapted to be secured to a vertical face of the ram frame, by means of bolts which pass through holes 12. The body is provided with a vertical bore 13, in which an outer vertically movable ram member 14 is a sliding fit. The

outer ram member 14 is moved up and down relatively to a fixed inner ram member 15, oil under pressure being applied to an end chamber of the ram through bores 16 in the inner member 15.

The outer ram member 14 is provided with longitudinal groove 17 having sloping side walls 18.

In the front of the guide sleeve there is a longitudinal sli-t 19 bounded by the fiat facing surfaces of two cheeks 20. Fitted in the slit 19 is a spacer comprising of an inner part 21 and an outer part 22. The inner part 21 has bevelled longitudinal edges which match the sloping sides 18 of the groove 17. Extending through the outer part 22 are several set screws 23, the inner ends of which enter bores in the inner part 21. The outer part 22 is clamped between the facing surfaces of the cheeks 20, the cheeks being drawn together by screws 24.

When wear of the guide sleeve and/or of the outer ram member 14 is such that adjustment is required, the screws 24 are removed and the spacer parts 21 and 22 are withdrawn and reduced in thickness, either by the removal of shims which may originally have been inserted between the sides of the spacer parts and the facing surfaces of the cheeks, or by grinding the spacer parts to make them slightly thinner. The spacer parts are then reinstated in the slit 19 and the screws 24 are replaced and tightened. This slightly reduces the diameter of the bore 13 and takes up the wear.

In the event of wear of the groove 17, or of the inner end of the inner spacer part 21, the latter can be moved radially inwards to take up this wear by adjusting the set screws 23. p

In the embodiment illustrated in Figures 1 and 2 the upper portion of the outer ram member 14 is screw threaded at 25, and an adjustable stop collar 26 is fitted on the threaded portion. This collar can be rotated on the screwed portion 25 in order to adjust its vertical position in relation to the outer ram member 14. It can be held in place by a locking device, for instance a lock nut, which is not shown. On the upper face of the guide sleeve there is provided a stop face 27 with which the stop collar 26 comes into contact when the ram is in its lower end position. In this embodiment. the upper end position of the ram is defined by an adjustable upper stop 28 which is engaged by the stop collar 26 to prevent The embodiment shown in Figure 4 is similar to that shown in Figures 1 and 2 except that in this case the guide sleeve is provided with two smaller vertical bores 29 and 30 laterally offset from the main bore 13. Each of these smaller bores is provided with a longitudinal slit 31, 32, and spacers 33, 34 are inserted in these slits. The smaller bores 29 and 30 receive guide rods which are attached to the platen of the machine, the object of these guide rods being to prevent tilting of the platen.

What we claim as our invention and desire to secure by Letters Patent is:

1. Hydraulic ram guide means comprising a longitudinally slidable ram member of circular cross-section, means defining a longitudinal groove in said ram member, a fixed guide sleeve having a longitudinal guideway of circular cross-section therein which slidably receives and guides said ram member, said guide sleeve also having two cheeks with parallel flat facing surfaces defining between them a longitudinal slit opening into said guideway, clamping means which can be tightened to draw said cheeks closer and reduce the width of said slit and tighten said guide sleeve around said rarn member, and a spacer member having parallel fiat side faces, said spacer member occupying said slit and adapted to be clamped firmly between said facing surfaces of said cheeks to define the width of said slit, and said spacer member having an inner end portion which projects from said slit into said guideway and said groove to prevent rotation of said ram member in said guide sleeve.

2. Hydraulic ram guide means according to claim 1 in which said groove in said ram member has sloping side walls, and said inner end of said spacer member has correspondingly bevelled edges, and in which there are means for adjusting the penetration of said inner end of said spacer member into said groove.

3. Hydraulic ram guide means according to claim 2 in which said spacer member comprises an inner part and an outer part, and said adjusting means comprises means for holding said inner part in an adjustable position in relation to said outer part.

References Cited in the file of this patent UNITED STATES PATENTS 

